The Particulate Nature of Matter：練習題

Which of the following processes involves a substance changing directly from a solid state to a gas state without passing through the liquid phase?

According to the particulate nature of matter, why can gases be easily compressed while solids cannot?

Which of the following processes provides the best evidence for the Particulate Nature of Matter by showing that particles are in constant, random motion?

A gas is contained within a sealed syringe. When the plunger is pushed inwards at a constant temperature, the volume decreases and the pressure increases. Based on the particulate nature of matter, why does the pressure increase?

Consider the phenomenon of diffusion where a drop of purple potassium manganate(VII) crystal is placed at the bottom of a beaker of still water. Over time, the entire beaker turns purple without stirring. Using the Particulate Nature of Matter, explain how the motion and collisions of water and solute particles lead to a uniform distribution.

A student sets up an experiment to demonstrate the diffusion of particles. A small crystal of potassium permanganate is carefully placed at the bottom of a beaker filled with 200 mL of distilled water. The beaker is left undisturbed at a constant temperature of \( 25^{\circ}C \).

(a) Using the particulate nature of matter, explain why the purple color gradually spreads throughout the water even though the beaker is not stirred. (2 marks)

(b) The experiment is repeated using a second beaker containing water at \( 60^{\circ}C \). Predict how the rate of color spreading will change compared to the first beaker. Explain your answer in terms of the kinetic energy of particles. (2 marks)

(c) If the same crystal were placed inside a sealed container of solid ice instead of liquid water, would the color spread as quickly? Justify your answer by comparing the arrangement and movement of particles in solids and liquids. (3 marks)